I've been recently doing a bit of research about signed languages because I have been in general looking at grammars (of mostly spoken languages) to investigate the functions and properties of conjunctions. I've also been thinking about linearization, from clearly non-linear (highly structured, in one way or another) meaning to a linear output in phonology over time.
The parallels between spoken languages and signed languages are remarkable, and I'm not questioning those at all. But I do think there are some fundamental differences in the signal.
Obviously there is one difference: spoken languages are produced orally with the vocal tract and perceived aurally with the ears; signed languages are produced manually with the hands (mostly) and perceived visually with the eyes. I think this may lead to other less obvious differences in the signal.
1. Conjunctions seem extremely rare in signed languages!
There are some, but they're semantically full. They're not the basic types like "that" or "and". Some spoken languages also lack overt conjunctions, but I haven't found any signed languages that have them. Why is this?
One possibility is that conjunctions are a special kind of diachronic residue that take a very long time to develop, more time than most signed languages have been around for. But that doesn't seem like a very strong argument. Another possibility is chance, but the proportions seem unlikely. That leaves a causal effect: something about signing means conjunctions don't develop. I'd say that suggests that signing doesn't require conjunctions. Why? The answer may be that the function is easily handled otherwise.
In several cases I've found that non-manual gestures, especially blinking (sometimes head nods, etc.), accompany the "non-overt conjunction" or clause boundary. In one case, I think a shoulder turn was used, suggesting a change of topic or perhaps additional information. I wonder whether these non-manual movements could actually be considered conjunctions!
So while I've found some interesting information, mostly about a widespread lack of conjunctions and the very intriguing possibility that they are encoded non-manually, I haven't found any general research on conjunctions in signed languages!
The only literature I've come across in any significant way is about the reported absence of subordination in signed languages, which, unsurprisingly, turned out to be very false. That mentions sometimes that there is no overt linker between clauses but rarely discusses it at all.
In general, I'd be very interested on data for conjunctions in signed languages if it exists (that was my original interest), but now I'd also like to know why they don't seem to exist in signed languages!
(Also, I'm not strictly interested in overt coordinators and subordinators. I'm just starting there because they're, obviously, the easiest to investigate. For covert conjunctions I first need to assume their existence. That's a later step of my project. In fact, I don't see them as very different anyway, but again it's just harder to analyze them at the surface level.)2. Although signed languages are still linearized, there are multiple channels.
The most obvious aspect is that two hands can be used at the same time for different purposes; I even found some discussion of two apparently independent sentences (overlapping temporally in the semantics) being articulated at the same time, one on each hand, as a kind of fast speech phenomenon, eliding the two-hand gestures as required. But at the very least, it would be easy to articulate, say, two nouns at the same time (perhaps instead of using a conjunction) with two hands. More than that, one hand might give additional information for what the other is conveying.
But beyond the hands, there are several other articulators like the eyes, face in general, head and shoulders, and perhaps others like the legs and feet.
So rounding down, there are at least three channels for signed languages-- two hands and the rest of the body. This is just not part of spoken language. Sure, there are instances of secondary articulation or consonants like "gb", but those are still with one general articulator (the mouth), and a single hand could easily do the same thing (eg, finger and thumb). What's interesting is that signed languages have up to double the basic articulatory space, plus additional ways to add to that like with the eyes. Spoken languages
could utilize gesture, but very very rarely does it seem to matter at a fundamental grammatical level (though I've heard of exceptions where, for example, demonstratives are formed with the hands-- an Australian language I heard about in passing. I should look up the reference).
One possible similarity for spoken language would be prosody. We can convey a lot on top of our words. So arguably we have two linear channels available. But then prosody would be available for signed languages too, of course.
This suggests two things:
1) Humans can produce and perceive multiple channels at one time, even if our primary means of producing speech is only with one articulator.
2) The medium of transmission affects the form. Multi-channel linearization gives signed languages more options. This also highlights that linearization has a major effect on language-- what we see (in linearized form) is far from whatever the underlying structure is.
Perhaps conjunctions don't exist within signed languages specifically because they're not as useful-- signed languages don't need to be as linearized or contain overt hints about relationships within the sentence.
I have found some general discussion here and there on the linearization and multi-articulator aspect of signed languages, but I haven't found any clear central source, still looking around.
So in general I'm interested in differences, but especially these two because they happen to be relevant for my research.
Sources on both would be much appreciated!
I'll also be taking ASL starting in a few weeks, so signing has been on my mind for that reason too. I look forward to the challenge is speaking without speaking (with my mouth-- I have a habit of using it a lot, perhaps too much). They say that a hard part of learning ASL is learning to not use one's mouth, but I think I'll actually be very good at it-- I type/chat/email so often that I have, I think, learned to channel my linguistic behavior away from my mouth as needed. But I'm sure it'll be a (fun) challenge
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Two other thoughts:
1. This lack of information might just be due to a general lack of information: the amount of research on signed languages is comparatively little, which, I'd say, shows a significant gap in research that should be filled. It's certainly interesting. Not my area, but it is catching my attention.
2. Transcriptions for signed languages are counterintuitive and, as far as I can tell, very uninformative. Obviously it's a challenge, but I'd like to either understand the existing system better (capitalized letters for the words basically) if I'm missing something or see a better system in place. But I might not be able to follow the real data anyway; hoping that might change next semester.
